System and method for determining parameters of patterned structures from optical data

Abstract

A control system and method are presented for use in optical measurements on patterned samples. The control system comprises a computer system configured for data communication with a measured data provider and comprising a data processor configured and operable to receive and process raw measured data of first and second types concurrently collected from the patterned sample being measured. said first and second types of the measured data comprising, respectively. scatterometry measured data. characterized by first relatively high signal-to-noise and predetermined first relatively low spatial resolution, and interferometric measured data characterized by second relatively low signal-to-noise and predetermined second relatively high spatial resolution, said data processor being configured to process the measured data to determine pattern parameters along said patterned sample characterized by said first signal to-noise and said second spatial resolution.

1 . A control system for use in optical measurements on patterned samples, the control system comprising a computer system configured for data communication with a measured data provider and comprising a data processor configured and operable to receive and process raw measured data of first and second types concurrently collected from the patterned sample being measured, said first and second types of the measured data comprising, respectively, scatterometry measured data, characterized by first relatively high signal-to-noise and predetermined first relatively low spatial resolution, and interferometric measured data characterized by second relatively low signal-to-noise and predetermined second relatively high spatial resolution, said data processor being configured to process the measured data to determine pattern parameters along said patterned sample characterized by said first signal to-noise and said second spatial resolution. 
     
     
         2 . The control system according to  claim 1 , wherein the data processor comprises:
 a data processing utility configured and operable to process the scatterometry measured data utilizing at least one of model-based or machine learning processing of said scatterometry measured data and extract an average value of at least one pattern parameter of the sample for each measured spot on the sample;   an optimizer utility configured and operable to process the interferometric measured data to transform each pixel-related interferogram of the interferometric measured data into a pixel-related spectrum, and utilize the scatterometry measured data to extract, from said each pixel-related spectrum, a spectral part matching the scatterometry data, and generate respective first and second matching spectra; and   a spectral analyzer utility configured and operable to analyze the first and second matching spectra and extract, from a spectral difference between the first and second matching spectra, distribution of pixel-related measured values of said at least one parameter in a pixel matrix of a size of the measured spot, and generate output data indicative of said distribution.   
     
     
         3 . The control system according to  claim 2 , wherein said output data is in the form of a map of the parameter's values for each of said at least one parameter. 
     
     
         4 . A system for measuring parameters of patterned samples comprising:
 a measurement system configured to concurrently perform scatterometric measurements and spectral interferometric measurements on each measured spot on the sample, the measurement system comprising: a broadband light source generating light propagating along an illumination channel towards the measured spot, an interferometric assembly, and a detection system comprising a spectrometer and a pixelated detector generating, respectively, first type measured data and second type measured data concurrently collected from the measured spot on the sample, being scatterometry measured data characterized by first relatively high signal-to-noise and first relatively low spatial resolution, and interferometric measured data characterized by second relatively low signal-to-noise and second relatively high spatial resolution; and   the control system according to  claim 1 .   
     
     
         5 . The system according to  claim 4 , configured and operable to selectively activate the interferometric assembly to collect said second type measured data and disactivate the interferometric assembly to collect the scatterometric measured data. 
     
     
         6 . A data analysis method for use in optical measurements on patterned samples to determine at least one pattern parameter of interest, the method comprising:
 providing raw measured data of first and second types concurrently collected from the patterned sample being measured, said first and second types of the measured data comprising, respectively, scatterometry measured data characterized by first relatively high signal-to-noise and first relatively low spatial resolution, and interferometric measured data characterized by second relatively low signal-to-noise and second relatively high spatial resolution,   processing said first and second types of the measured data to determine each of said at least one parameter of interest with said first signal to-noise and said second spatial resolution.   
     
     
         7 . The method according to  claim 6 , wherein said processing comprises:
 applying at least one of model-based and machine learning processing to the scatterometry measured data to extract an average value of at least one pattern parameter of the sample for each measured spot on the sample;   processing the interferometric measured data to transform each pixel-related interferogram of the interferometric measured data into a pixel-related spectrum,   utilizing the scatterometry measured data to extract, from said each pixel-related spectrum, a spectral part matching the scatterometry data, and generating respective first and second matching spectra; and   analyzing the first and second matching spectra and extracting from a spectral difference between the first and second matching spectra, distribution of pixel-related measured values of said at least one parameter in a pixel matrix of a size of the measured spot and generating output data indicative of said distribution.